The present invention relates to a lifting system for raising and lowering interchangable freight containers adapted to be hauled by automotive trucks. These containers are in daily use throughout the world and are commonly seen transported by common carriers via ships, trains and trucks, withh diverse lines of commodities, limited only in that size of cargo not exceed dimensional physical confines of container. Containers are normally of standard height and width, varying only in length. Standard available lengths are 20, 40, and 45 feet.
In the past various types of structures and systems have been used for raising and lowering the portable cargo containers from a truck. Most of these systems require hydraulic jacks that are structurally mounted on the corners of the cargo containers. This type of structure is illustrated in U.S. Pat. No. 3,476,275 of Cowlishaw et al., in U.S. Pat. No. 3,749,363 to Houser, and in U.S. Pat. No. 4,053,073 to Franchin.
Another approach has been to have support legs pivotally attached to the bottom of the cargo containers so that they may be unloaded and stand on their own. This type of structure is illustrated in U.S. Pat. No. 3,632,072 to Blackburn and in U.S. Pat. No. 3,773,199 to Arvidsson.
Another approach has been to have the hydraulic jacks mounted on the frame of the truck and utilize these for lifting the cargo container off the frame. This structure is illustrated in U.S. Pat. No. 3,817,413 to Ham.
Of the different systems and structures already devised, each have their own individual drawbacks. The structures having the jacks mounted on the cargo containers would require brand new cargo containers to be manufactured and could not be used with existing cargo containers. Likewise the system that has the hydraulic jacks mounted on the frame of the truck would require modification of the existing truck frames and also require new cargo containers to be used therewith.
Applicant's novel system would allow existing cargo containers to be used without the necessity of modifying their structure. Also it would not be necessary to modify the truck or its frame to utilize applicant's system. Furthermore, a set of the four jack attachment brackets and four screw jacks are basically all that would be necessary in order to utilize the system.
It is an object of the invention to provide a novel system for raising and lowering portable cargo containers that could be used with existing cargo containers without the need to modify them.
It is also an object of the invention to provide a novel system for raising and lowering portable cargo containers that does not require the truck or its frame to be modified in order to use the system.
It is another object of the invention to provide a novel system for raising and lowering portable cargo containers having unique jack attachment brackets. It is an additional object of the invention to provide a novel system for raising and lowering portable cargo containers that can be installed and removed by the truck driver.
It is a further object of the invention to provide a novel system for raising and lowering portable cargo containers that is economical to manufacture and market. This invention is totally portable and can therefore be used on any length of container, but not necessarily restricted to aforementioned containers, as its concept in utility and convenience are only limited in scope by the needs, ingenuity, and prudent means by which its wide range of applications may be safely attained. Any location accessible by a single heavy-duty truck or railroad is all that is needed to use the system. The invention also opens the potential of decreasing costs of operation in reducing the conventional trailer population, thereby saving fleets license fees, insurance fees, maintenance fees, warehouse fees, etc., and other costs and charges inherent to the industry as it is now known to incurr, due to the nature and present day limitations of the business. Benefits of the invention are just too numerous and broad to cover at this time; but the possibilities of application will have been opened to a wide spectrum of uses due to its simplicity, portability, practicality, and feasibility.